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Edmonton, Canada

Nicholsa M.A.,Massey University | Savidov N.A.,Alberta Agriculture
Acta Horticulturae | Year: 2012

Aquaponics is the land based production of fish in tanks combined with the recirculation of the water from the fish tanks through hydroponic systems to produce high value horticultural crops. The waste products from the fish are converted by a bio-filter into soluble nutrients which are absorbed by the plants, and allow "clean" water to be returned back to the fish. Thus it produces valuable fish protein with a minimal pollution of fresh water resources, while at the same time producing horticultural (usually vegetable) crops. The production of fertilizers is becoming increasingly expensive due to high prices of fossil fuels, and this may have long term implications for nutrient use in agriculture in the future, particularly in developing countries. Aquaponics uses waste products derived from animals and plants which are fed to the fish, and thus converted into valuable animal protein and fresh vegetables. With the world's fresh water resources limited, aquaponics would appear to have considerable potential for developing countries. Source


Malhi S.S.,Agriculture and Agri Food Canada | Nyborg M.,University of Alberta | Solberg E.,Alberta Agriculture | Wang Z.-H.,Agriculture and Agri Food Canada | Henriquez B.,Alberta Agriculture
Journal of Plant Nutrition | Year: 2011

Most soils in the Prairie Provinces of Canada are deficient in plant-available nitrogen (N), and many soils in the Parkland region also contain insufficient amounts of plant-available sulfur (S) for high crop production. A field experiment with perennial grass stand was conducted to determine the effects of long-term annual N (112 kg N ha -1), S (11 kg S ha -1) and potassium (K) (40 kg K ha -1) fertilization, and one-time lime application on forage dry matter yield (DMY) and soil properties [pH, total organic carbon (TOC) and N (TON), and light fraction organic C (LFOC) and N (LFON)] on a Dark Gray Chernozem (Boralfic Boroll) loam at Canwood in north-central Saskatchewan, Canada. The experiment had surface-broadcast annual treatments of no fertilizer (Nil), N, S, NS, and NSK fertilizers from 1980 to 2002, and one-time lime application in 1992 to bring soil pH to about 7. Application of N or S alone had only a little effect on DMY compared to unfertilized Nil treatment, while application of both NS together substantially increased DMY, and forage yield was further increased when K was also applied (NSK). The DMY following onetime liming was greater in limed plots than in unlimed plots for at least 10 years. Decline of soil pH by fertilization mainly happened in the 0-10 cm depth with N only, and in the 0-5 cm layer with NS treatment, whereas these treatments tended to increase soil pH in layers below 10 cm. Onetime surface application of granular lime increased soil pH, mainly in the 0-5 cm layer, and the effect was maintained for at least 9 years. Mass of TOC, TON, LFOC, and LFON in different soil layers increased with combined applications of N and S fertilizers (NS), but the effect was much more pronounced in the 0-7.5 cm soil layer, and also varied with organic fraction. Light organic fractions were more responsive to applied NS than total organic fractions. The findings suggest that application of N and S together was effective in sustaining high forage yield and increasing C and N sequestration in a soil deficient in both N and S. © Crown Copyright. Source


Gossen B.D.,Agriculture and Agri Food Canada | McDonald M.R.,University of Guelph | Conner R.L.,Agriculture and Agri Food Canada | Hwang S.-F.,Alberta Agriculture | Chang K.-F.,AAFRD
Canadian Journal of Plant Pathology | Year: 2010

Mycosphaerella blight (Mycosphaerella pinodes) is the most important disease of field pea (Pisum sativum) in western Canada, occurring in almost every field each year. The objective of the study was to assess the impact of seed infection on epidemics of mycosphaerella blight. In preparation for the trial, seed lots of a susceptible and partially resistant cultivar with different levels of seed infection with M. pinodes were produced at a single site with uniform handling and storage conditions. Field trials were conducted in 2005 and 2006 at three sites in western Canada where levels of external inoculum were high (Vegreville, AB, Saskatoon, SK, Morden, MB), and one site (Bradford, ON) with little external inoculum. For each cultivar, the seed infection treatments were: (i) high seed infection (26-47% of seed infected with M. pinodes); (ii) intermediate seed infection (6-15% of seed infected); (iii) fungicide - intermediate seed lot treated with a fungicide to minimize seed transmission; and (iv) low seed infection (0-2% of seed infected). Seedling establishment was higher in the low seed infection treatment than the other treatments in four of eight station years, but there were no consistent differences among the other treatments. There were small differences in blight severity among treatments in several station years, but no differences were observed at Bradford, the site with minimal external inoculum. We conclude that seed infection with M. pinodes does not contribute substantially to above-ground symptoms in the year of planting. However, very high levels of seed infection reduced seedling establishment, so continued seed testing for germination is recommended. © Her Majesty the Queen in Right of Canada. Source


Malhi S.S.,Agriculture and Agri Food Canada | Nyborg M.,University of Alberta | Goddard T.,Alberta Agriculture | Puurveen D.,University of Alberta
Nutrient Cycling in Agroecosystems | Year: 2011

Long-term use of soil, crop residue and fertilizer management practices may affect some soil properties, but the magnitude of change depends on soil type and climatic conditions. Two field experiments with barley, wheat, or canola in a rotation on Gray Luvisol (Typic Cryoboralf) loam at Breton and Black Chernozem (Albic Argicryoll) loam at Ellerslie, Alberta, Canada, were conducted to determine the effects of 19 or 27 years (from 1980 to 1998 or 2006 growing seasons) of tillage (zero tillage [ZT] and conventional tillage [CT]), straw management (straw removed [SRem] and straw retained [SRet]) and N fertilizer rate (0,50 and 100 kg N ha-1 in SRet, and 0 kg N ha-1 in SRem plots) on pH, extractable P, ammonium-N and nitrate-N in the 0-7.5, 7.5-15, 15-30 and 30-40 cm or 0-15, 15-30, 30-60, 60-90 and 90-120 cm soil layers. The effects of tillage, crop residue management and N fertilization on these chemical properties were usually similar for both contrasting soil types. There was no effect of tillage and residue management on soil pH, but application of N fertilizer reduced pH significantly (by up to 0.5 units) in the top 15 cm soil layers. Extractable P in the 0-15 cm soil layer was higher or tended to be higher under ZT than CT, or with SRet than SRem in many cases, but it decreased significantly with N application (by 18.5 kg P ha-1 in Gray Luvisol soil and 20.5 kg P ha-1 in Black Chernozem soil in 2007). Residual nitrate-N (though quite low in the Gray Luvisol soil in 1998) increased with application of N (by 17.8 kg N ha-1 in the 0-120 cm layer in Gray Luvisol soil and 23.8 kg N ha-1 in 0-90 cm layer in Black Chernozem soil in 2007) and also indicated some downward movement in the soil profile up to 90 cm depth. There was generally no effect of any treatment on ammonium-N in soil. In conclusion, elimination of tillage and retention of straw increased but N fertilization decreased extractable P in the surface soil. Application of N fertilizer reduced pH in the surface soil, and showed accumulation and downward leaching of nitrate-N in the soil profile. © 2010 Springer Science+Business Media B.V. Source


Malhi S.S.,Agriculture and Agri Food Canada | Nyborg M.,University of Alberta | Goddard T.,Alberta Agriculture | Puurveen D.,University of Alberta
Nutrient Cycling in Agroecosystems | Year: 2011

Long-term use of soil, crop and fertilizer management practices alters some soil properties, but the magnitude of change depends on soil type and climatic conditions. A field experiment with a barley (Hordeum vulgare L.)-wheat (Triticum aestivum L.)-canola (Brassica napus L.) rotation was conducted on a Gray Luvisol (Typic Cryoboralf) loam soil at Breton, Alberta, Canada. Effects of 19 or 27 years (from 1980 to 1998 or 2006 growing seasons) of tillage (zero tillage [ZT] and conventional tillage [CT]), straw management (straw removed [S Rem] and straw retained [S Ret]) and N fertilizer rate (0,50 and 100 kg N ha -1 in S Ret, and 0 kg N ha -1 in S Rem plots) were determined on total organic C (TOC) and N (TON), light fraction organic C (LFOC) and N (LFON), macro organic matter C (MOM-C) and N (MOM-N), microbial biomass C (MB-C), and mineralizable C (C min) and N (N min) in the 0-7.5 and 7.5-15 cm or 0-5, 5-10 and 10-15 cm soil layers. Zero tillage and S Ret tended to have higher, and N fertilizer treatment usually had higher mass of TOC, TON, LFOC, LFON, C min and N min in soil compared to the corresponding CT, S Rem and zero-N control treatments, especially in the surface soil layers. Soil MB-C, MOM-C and MOM-N in soil generally tended to be higher with S Ret than S Rem, and also with N fertilizer than zero-N. There was no additional beneficial effect of ZT in increasing MB-C in soil. There were close and significant correlations among most soil organic C or N fractions, except for MB-C which did not correlate with MOM-N, and N min did not correlate with MOM-C. Linear regressions between crop residue C input and soil organic C or N were significant in most cases, except for MB-C and N min. Compared to the 1979 data, all treatments that did not receive N fertilizer (CTS Rem0, CTS Ret0, ZTS Rem0 and ZTS Ret0) showed a decrease in TOC concentration in the 0-15 cm soil layer over time, with the highest decrease in the CTS Rem0 treatment. Straw retention and N fertilizer application at 50 and 100 kg N ha -1 under both ZT (ZTS Ret50 and ZTS Ret100) and CT (CTS Ret50 and CTS Ret100) resulted in a strongest increase in TOC during the first 11 years, and since then the TOC decreased under both N rates but 50 kg N ha -1 rate under CT (CTS Ret50) showed the strongest negative effect on TOC in soil. In conclusion, elimination of tillage, straw retention and N application all improved organic C and N in soil, and generally differences were more pronounced for light fraction organic C and N, and between the most extreme treatments (CTS Rem0 vs. ZTS Ret100) for each dynamic organic fraction. This may be better for the long-term sustainability of soil quality and productivity. © 2010 Springer Science+Business Media B.V. Source

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